TAVR a durable remedy for those not eligible for open heart surgery

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Trans-catheter aortic valve replacement (TAVR), a minimally invasive procedure used to replace heart valves without open heart surgery appears to provide a durable remedy, found a Duke analysis.

The procedure, called trans-catheter aortic valve replacement (TAVR), has been safely used in older patients who are not good candidates for open heart surgery. But strong research establishing its durability over five to 10 years has been lacking. This has created questions about whether it should be used in younger and healthier people.

Now a study led by a member of the Duke Clinical Research Institute, provides some answers. Using data and follow-up from the first and largest studies of TAVR safety, the research team found that the biologic valves used in a TAVR procedure, as well as those used in open heart surgery, continue to perform well up to five years after implantation.

“I think these findings are incredibly reassuring at least out to five years,” said lead author Dr Pamela Douglas, the Ursula Geller professor for research in cardiovascular diseases at Duke University School of Medicine and director of the DCRI imaging program11 am. “The valve is quite durable and safe.”

Douglas and colleagues analysed data from more than 2,700 patients who had been part of a large trial called PARTNER, which established the safety of TAVR. The study patients received either a minimally invasive TAVR procedure – which uses a catheter that is routed through a blood vessel in the leg or chest to access the heart – or an open-heart surgery to replace the valve.

All of the study patients received biological valves, developed from animal or donated human tissue. Biological valves are increasingly favored over mechanical valves, which must be surgically implanted and require long-term use of anti-coagulation drugs to protect against blood clots.

In their analysis, the study authors also included echocardiograms of about 475 patients five years after either their minimally invasive or surgical valve replacement. The average age of patients in the study group was 84.5 years, and many had additional serious health risks.

Among the 2,404 TAVR patients in the study, 34% survived five years. Similarly, 37% of the 313 patients whose valves were replaced in an open surgery also survived to five years. Twenty TAVR patients (0.8%) required a second valve procedure, and only five of the revisions arose from structural deteriorations of the valve.

The researchers found evidence that 3.7% of the TAVR patients developed a condition in which the valve allowed blood to flow back into the heart, and this problem increased over time.

“This was seen in only a handful of patients, but it’s certainly something of concern and warrants further study,” Douglas said. “Overall, however, the findings from this carefully designed study demonstrate that there is little evidence of valve failure or deterioration for either TAVR or surgery using biological valves.”

She said the study provides a first step in understanding the long-term benefits of minimally invasive valve replacement, and suggests additional studies could be safely undertaken.

Abstract
Importance: Use of transcatheter aortic valve replacement (TAVR) for severe aortic stenosis is growing rapidly. However, to our knowledge, the durability of these prostheses is incompletely defined.
Objective: To determine the midterm hemodynamic performance of balloon-expandable transcatheter heart valves.
Design, Setting, and Participants: In this study, we analyzed core laboratory–generated data from echocardiograms of all patients enrolled in the Placement of Aortic Transcatheter Valves (PARTNER) 1 Trial with successful TAVR or surgical AVR (SAVR) obtained preimplantation and at 7 days, 1 and 6 months, and 1, 2, 3, 4, and 5 years postimplantation. Patients from continued access observational studies were included for comparison.
Interventions: Successful implantation after randomization to TAVR vs SAVR (PARTNER 1A; TAVR, n = 321; SAVR, n = 313), TAVR vs medical treatment (PARTNER 1B; TAVR, n = 165), and continued access (TAVR, n = 1996). Five-year echocardiogram data were available for 424 patients after TAVR and 49 after SAVR.
Main Outcomes and Measures: Death or reintervention for aortic valve structural indications, measured using aortic valve mean gradient, effective orifice area, Doppler velocity index, and evidence of hemodynamic deterioration by reintervention, adverse hemodynamics, or transvalvular regurgitation.
Results: Of 2795 included patients, the mean (SD) age was 84.5 (7.1) years, and 1313 (47.0%) were female. Population hemodynamic trends derived from nonlinear mixed-effects models showed small early favorable changes in the first few months post-TAVR, with a decrease of −2.9 mm Hg in aortic valve mean gradient, an increase of 0.028 in Doppler velocity index, and an increase of 0.09 cm2 in effective orifice area. There was relative stability at a median follow-up of 3.1 (maximum, 5) years. Moderate/severe transvalvular regurgitation was noted in 89 patients (3.7%) after TAVR and increased over time. Patients with SAVR showed no significant changes. In TAVR, death/reintervention was associated with lower ejection fraction, stroke volume index, and aortic valve mean gradient up to 3 years, with no association with Doppler velocity index or valve area. Reintervention occurred in 20 patients (0.8%) after TAVR and in 1 (0.3%) after SAVR and became less frequent over time. Reintervention was caused by structural deterioration of transcatheter heart valves in only 5 patients. Severely abnormal hemodynamics on echocardiograms were also infrequent and not associated with excess death or reintervention for either TAVR or SAVR.
Conclusions and Relevance: This large, core laboratory–based study of transcatheter heart valves revealed excellent durability of the transcatheter heart valves and SAVR. Abnormal findings in individual patients, suggestive of valve thrombosis or structural deterioration, were rare in this protocol-driven database and require further investigation.

Authors
Pamela S Douglas; Martin B Leon; Michael J Mack; Lars G Svensson; John G Webb; Rebecca T Hahn; Philippe Pibarot; Neil J Weissman; D Craig Miller; Samir Kapadia; Howard C Herrmann; Susheel K Kodali; Raj R Makkar; Vinod H Thourani; Stamatios Lerakis; Ashley M.Lowry; Jeevanantham Rajeswaran; Matthew T Finn; Maria C Alu; Craig R Smith; Eugene H Blackstone

Duke University Medical Centre material
JAMA Cardiology abstract


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